Lobular type of pump



Jan. 25, 1966 B. K. JAQUITH LOBULAR TYPE OF PUMP Filed June 2, 1964 IN V EN TOR.

ATTORN BURTON K. JAQUITH United States Patent 3,231,179 LOBULAR TYPE OF PUMP Burton K. Jaquith, Fort Lauderdale, Fla., assignor to Technical Industries, lnc., Fort Lauderdale, Fla, a corporation of Florida Filed June 2, 1964, Ser. No. 371,924 13 Claims. ((31. 230205) This invention relates to a well-known type of pump in which a volume of gaseous fluid entering through an inlet into a housing is squeezed out therefrom through a delivery outlet in response to rotation of intermeshing lobular impellers closely fitted within the housing, these impellers acting to carry the fluid around within the spaces therewithin to the point of delivery. Such a pump is adapted to operate equally well on pressure or suction, or any combination of the two. It has the advantage of relatively positive displacement and capacity for high speed operation without lubrication of the parts swept by the air or other gaseous fluid which is acted upon. In order to eliminate rubbing friction, the impellers in this type of pump are dimensioned so as to provide only very small clearance between themselves and the housing in which they operate. A small clearance of from .002" to .005, which is common, insures that the surfaces of the impellers themselves will not touch either each other or the surrounding housing at any point in their operation. The impellers are driven oppositely in proper registry with one another, as by gearing contained in a separate adjoining compartment, so that their lobes are relieved of any driving duty.

In spite of these meritorious features, a pump of this type, when operated on vacuum, can efficiently produce no more than, 12" Hg or so, thereby disqualifying itself for use in many fields Where higher vacuum levels are required. The present invention which is concerned with a means and method applicable to such a pump overcomes this serious limitation to a very considerable extent. It provides therefor a safe liquid seal Within the clearance spaces between and around the lobular impellers and, in the case of vacuum operation, produces a substantial rise in the vacuum level attained. This is an important desideratum, in the dairy industry for example, where a minimum of Hg or so is required for milking operations. This higher level attainable by my invention may even be safely advanced to a point in excess of Hg when the pump is properly equipped and operated in accordance with the means and method herein to be described.

An important objective attained by this invention is the absence of cooperating parts which are expensive, short lived, or sensitive. This is accomplished by utilizing a conduit system through which is flowed a liquid which serves both as a sealant and coolant when delivered into the pump to be circulated through the clearance spaces around and between its rotating impellers. in the process of its advance within the pump, the liquid is converted into atomized particles of minute size. In such a state the liquid may freely enter into the very narrow clearance spaces to be sealed whereas, because of its incompressibility in the normal liquid state, this would be wholly unsafe, if not impossible.

A further objective attained by this invention is the utilization of the atomized sealant in the further capacity of a cooling medium whereby to transfer to the atmosphere a substantial portion of the heat generated by compression of the gas in response to its forced displacement by the impellers. A rise in temperature always accompanics operation of this type of pump to impose a limit to the speed at which it may be safely operated. This increase in ambient temperature results primarily from creation of a pressure differential between the incoming and outgoing gas containing the same thermal units which, in turn, requires confinement of these thermal units within a lesser volume of space, thereby generating an increase in its relative temperature. By utilizing a circulating sealant which is also a cooling medium, the rate of temperature rise is reduced to a point which permits faster pump operation with safety, thereby increasing its CFM output.

Other objects and advantages also are derived from the present invention including, inter alia, an effective filter for separating foreign particles from the gaseous stream being drawn into the pump, all such particles being deposited in a liquid pool which automatically drains itself whenever operation of the pump is stopped and refills itself whenever the operation is resumed. This is a safety factor because of the ever-present possibility that some foreign particles will include small pieces of scale, rust or other solid matter Whose presence Within the pump might be damaging to the surfaces therewithiu which define the very small clearance spaces required in a lobular type of pump.

In the discussion to follow, the lobular pump illustrated and described, by way of example, is treated as operated on suction, as would be required in the case of milking machines. The present invention, without modification, is equally applicable to pumps of lobular type when operated on pressure, and it should be so understood in any interpretation of the specification and claims herein. Also, air which is repeatedly referred to as the gaseous medium introduced into and discharged from the pump, is to be considered as merely representative of any gaseous media derived from an atomizable sealing liquid, e.g. various hydrocarbons, refrigerants, etc., capable of effective handling by a pump of the lobular type, and the term air, as used herein, should be so understood.

A suggestive embodiment of this invention is illustrated in the accompanying drawing wherein FIGURE 1 is a sectional view through a conventional lobular type of pump, taken transversely of the axes of its impeller shafts, the several units comprised in the sealant-coolant system applied to the pump being shown variously in section, elevation and/ or diagram; and

FIG. 2 is a detail in section, taken transversely of the impeller shafts within the gear compartment of the pump at one end of the impeller housing.

The pump, as illustrated, comprises two parallel shafts 1t) and 11 mounting fast a pair of lobular impellers 12 and 13 adapted to be rotated oppositely in registry with each other by intermeshing gears 14 and 15 (FIG. 2) carried fast on the two shafts to establish a driving connection therebetween. A pulley 16 mounted fast on one shaft is driven by an endless belt 17 which passes over and around a second pulley 18 'on the drive shaft 19 of an electric motor M.

The intermeshing gears and lobular impellers are enclosed within a closely-surrounding, slightly elongated, housing H having a pair of spaced end walls 20 (one only being shown) which supports suitable bearings for the shafts 10 and 11, also a compartment 21 which encloses the gears 14 and 15. These end walls of the housing are aflixed and sealed to a continuous peripheral wall 22 having opposite ends curved through degrees about centers which coincide with the axes of the proximate shafts. At spaced points the housing peripheral wall 22 is interrupted by two openings into which nipples 24 and 25 are securely fitted to provide an inlet and outlet, respectively. As shown, the inlet nipple 24 is extended upwardly from the housing top, providing an elongate fluid dispersing or atomizing chamber, the outlet nipple being depended from its bottom.

The motor M rests upon four legs which terminate in out-turned feet 28 formed with holes or slots, as is usual, for reception of attaching bolts 29. Similarly, the pump housing H is provided with four depending legs having out-turned feet 30 with the usual holes or slots for reception of attaching bolts 31. For convenience, the pump and motor are mounted upon a common elongated base B, desirably a casting of aluminum or aluminum alloy, the better to serve as a cooling unit as hereinafter noted. This base comprises a rectangular cover having a top 32 with depending side and end walls 33 and, complementary thereto, a pan having a bottom 34- with side and end walls 35 upstanding therefrom. Ribs or fins 36 are extended outwardly from the side and end walls of the cover and pan to greatly increase the area of their exterior surfaces, thereby to augment their thermal dissipating capacities.

Formed on the base top 32 in one end portion thereof is a rectangular block 39 of increased thickness to furnish a strengthened supporting area whereon the pump feet 30 may be rested. Tapped holes for the attaching bolts 31 are formed in this block to secure the pump housing fixedly thereto. An opening through the central portion of the block and base top therebelow closely receives the depending outlet nipple 25 to which is fitted a sealing gasket 40 resting upon the base top to be engaged by an adjustable nut 41 applied to the nipple body. The discharge end of the outlet nipple terminates below the base top at a point relatively close to one end thereof. The motor feet 28 are rested upon a block 4-2 which is also secured fixedly to the base top 32. The attaching bolts 20 engage with tapped holes in this block to secure the motor adjustably or fixedly thereto, as desired.

A flange 45 is extended continuously around the walls 33 of the base cover, being out-turned from its lower edges to rest upon a similar flange 46 out-turned from the top edges of the pan walls 35. As by bolts 47 traversing there two flanges, the base cover and pan may be locked together, with suitable gasketing therebetween, to provide a unitary, fully enclosed chamber within the base adapted to serve as a tank or reservoir in a liquid circulation system presently to be described. Depending from the pan bottom are legs 49 each provided with a foot 50 which, when rested upon a suitable horizontal support, will maintain the base in a level elevated position thereabove, I also provide in the pan bottom 34 a drain opening to which is fitted a plug or valve 51; also extending through one of its end or side walls is an inlet 52 equipped with a valve 53 having a control float 54 therefor. When connected, as by a tube 55, with a source of liquid, such as water, this valve will operate to shut off the incoming liquid at a predetermined level where it is automatically maintained during periods of pump operation. This level is well below the base top 32 so as to maintain at all times an air chamber above the liquid surface within the tank. Near one end of the base top 32 is a discharge opening 56 fitted with an upstanding nipple 57 for dis charge of air heated by the pump and driven thereby through the outlet nipple 25 into the opposite end of the air chamber. During its movement through the chamber, heat carried by the air is transferred to the body of liquid within the tank, also to the walls thereof through which it is further transferred for dissipation into the atmosphere with assistance from the fins exteriorly of the tank.

A tube 6% depends from the base top 32 into the tank to a point close to its bottom in the end portion thereof which is proximate to the discharge opening 56. Above the base the tube is connected to an L fitting 61 from which a tube 62 is extended to a liquid circulation line 63. Interposed in this tube 62 is a 3-position valve 64 having a rotable plug with an angular port transversely extended therethrough to open out at two spaced points 90 degrees apart, one communicating with a further tube 65 leading to a circular head 66 which surrounds the inlet nipple 24 in spaced relation thereto. This head which is fixedly secured to the nipple is provided with a circular cap 67 having a crown 68 overlying the open top of the nipple 24 in spaced relation thereto. A flanged central opening 69 is formed through the crown to receive the end portion of a conduit pipe 70 which is securely attached and sealed thereto. This conduit pipe leads to the closed space from which air is to be educted in response to operation of the pump.

With the cap applied to the head and sealed thereto, a closed chamber is provided through which all air must pass while en route to the pump. It is important that no foreign particles be allowed to enter into the pump along with the air, so a filter for separation of all solid particles, no matter how small, is located at this point. As shown, it comprises a horizontally disposed shield 71 having downwardly curved peripheral walls '72 which terminate short of the circular head walls so as to leave an annular space therebetween. Support for this shield is furnished by the top edges of a plurality of radial wings 73 upstanding from the bottom of the head to a common level which is slightly below the top of the inlet nipple 24. This shield acts to deflect the incoming air stream first radially and outwardly over its top face, then radially and inwardly below the shield peripheral edges, then somewhat upwardly therewithin, and finally, when opposite the open upper end of the inlet nipple, reversely in a downward direction, all in response to the powerful suction force created by the lobular impellers rotating within the housing H. When the swiftly-moving air stream is first deflected radially and outwardly, it also is directed downwardly straight toward a liquid pool contained within the annular space between the head 66 and nipple, It then inescapably impinges upon the surface of this pool. Any foreign particles then carried by the air stream will have a momentum factor, because of their greater specific gravity, such as to induce their separation from the air stream for deposit on or in the pool. By this means, an effective filter is provided to prevent passage of small solid particles into the pump, with probable resulting damage thereto.

In the connection between the tube 65 and the head 66 an orifice fitting 75 is utilized. This is coupled to the end portion of the tube and screw threaded into a tapped hole provided for its reception in a wall of the head at an elevation somewhat below the downturned peripheral portion 72 of the shield 71. The internal diameter of this fitting is sized so as to restrict the flow therethrough of liquid to a predetermined amount which is proportionate to the impeller-created pressure differential existing between opposite sides of the pump. The liquid, upon passing through the orifice fitting, accumulates in the bottom portion of the head to form therein the annular pool which is free to rise to a level about even with that of the orifice itself. At this same level a plurality of spaced-apart ports 76 are extended radially through the inlet nipple 24. Following the creation of such a pool, so long as a constant inflow of liquid proceeds through the tube 65, surface liquid in a small amount Will spill therefrom into these ports to drain therethrough and into the inlet nipple where it is immediately subjected to three strong forcesgravity, pump-induced suction, and impingement from the rapidly moving air stream. A state of turbulence which is then created within the head, tends also to agitate and roughen the pool surface. A tapped opening in the side of the cap 67 receives a fitting 77 from which a tubular connection may be extended to a near-by gage which registers the approximate vacuum level maintained in the inlet during periods of pump operation.

At or about the bottom of the head 66 is a drain opening occupied by the housing 78 of a gravity-operated ball check valve 79 which is normally drawn upwardly against a seat therefor in response to operation of the pump to close an axial passageway through the valve. The housing of this valve is connected also through a tubing 81 with an inlet fitting 82 in the base top 32 so that, when the check valve is open in response to unopposed gravity, liquid draining from the annular chamber in the head 66 will be free to pass through the tubing and into the base tank. This can take place only when operation of the pump is stopped, purposely or otherwise. When it does occur, the pool level within the head 66 drops below the level of the drain ports 76, thereby halting further flow of liquid within the head into and through the inlet nipple 2.4. During periods of pump operation, all particles separated from the air stream passing by and under the shield 71 are deposited in the pool so as to be automatically removed from the head chamber along with the liquid therein, at the conclusion of each pump operating period.

Performance data concerning operation of a lobular type of pump equipped with the sealant-coolant system herein disclosed, is presented at this point:

Pumporiginal rated capacity, 31 c.f.m., 12" Hg, at

1100 r.p.m.

Conversionbase mounting both pump and motor, the latter rated at H.P.; interior of base providing tank forming part of closed circulation system along with head fixedly mounted over inlet nipple, all as specified herein.

Operationpump speed maintained continuously at 2200 r.p.m., producing an output of 47 c.f.m. at Hg, or 122 free air c.f.m.

Temperatures etc.-water in tank about 30 degrees F. above ambient; water loss, through vaporization, about 1 gallon per hour; orifice Mt diameter controlling water admission into head at approximately 1.6 gallons per minute fiow; water temperature at impellers, about 2.0 degrees F. below ambient; air at discharge outlet from pump, less than 135 degrees F.

Certain instruments aifording control and safety to the pump operation are also installed in the tank, one being a normally-closed thermostat 84 which is supported therein directly below the pump outlet nipple 25 and within the air space above its liquid level; another, a second normally-open thermostat 85 which is wholly submerged within the liquid when at its normal level, and in connection with an electric heater d6, also submerged within the liquid, to be operated automatically in cold weather when danger from possible freezing exists. These several instruments are electrically connected into a wiring system which, in a simplified form, may comprise a grounded circuit, also a wire conductor 8'7 leading from a current source to a magnetic motor starter which includes manually operable start and stop switches 88 and 89, respectively. Wire connections 0 and E i are also extended to the thermostats $4 and 35, respectively, to supply current thereto for operation thereof. Current is furnished to the motor M through a conductor wire 92 leading from the magnetic motor starter. Since all such instruments are Well known at the present time, no further description thereof is deemed necessary. Suffice to say, if and when the temperature within the tank rises to a dangerous point, the thermostat 84, set at 135 degrees F. or so to open the circuit through the wire 90, will cause the motor to stop, thereby alerting the attendants to ascertain and rectify the cause therefor. The otier thermostat 35, set at 40 degrees F. or so, will be automatically operated at that temperature to close the circuit through the wire 91 so that operation of the heater as may be started to prevent possible damage resulting from freezing in cold Weather of the liquid, particularly water if that be used.

The efficiency of a lobular type of pump, such as the one herein described, depends largely upon the degree and uniformity of the clearance spaces provided between the lobular impellers themselves and between the impellets and the housing which closely surrounds them. During each impeller rotation, the outer end portion of each lobe moves past a full 180 degrees of one curved end portion of the housing and a lesser distance past the waist portion of its companion impeller. The spaces separating each impeller from the housing and from its companion impeller during these portions of its cyclic movement are usually reduced close to the very minimum-too close, for example, to accommodate therewithin any water when in its normal state of liquidity. It is necessary that this be so, otherwise the air displaced by the impellers would be free to leak past their rotating lobes with consequent diminution in the c.f.m. output. The problem of heat generated by compression of air within the pump housing is always present. This increases with mounting speed in operation of the impellers up to a limit of perhaps 4500 r.p.m. Beyond this point such a pump may not be continuously operated with safety in most cases. While a liquid seal within the housing might ideally increase the safety limit, any such step has been considered both impractical and impossible because of the factor of incompressibility which is involved in such a sealant when required to operate within the high thermal and close spatial conditions present within such a pump. These obstacles are overcome by the means and method of this invention, as will be fully explained at this point.

Water, for example, when added in controlled amounts to the air stream entering into the pump, is dispersed and almost immediately converted to an atomized state. This is due to the severity of the forces whichsuddenly act upon it when first entering the air inlet. Its physical structure is reduced to a fraction of its former size so as to be conditioned for effective occupancy of the very narrow clearance spaces Within a lobular type of pump. In this condition it is continuously move-d through the pump without damage to any parts or surfaces interiorly of the housing. Its presence therewithin does, however, provided an eifective sealant which operates to minimize back-leakage through the clearance spaces above noted, thus increasing the c.f.m. output of the pump. This feature of advantage is supplemented by one other very important factor-the coolant capacity of the liquid so introduced into the pump. This liquid, particularly water, may be drawn from a circulating line where it is always fresh and stable in temperature, or it may be water which is circulated and recirculated through a closed conduit system which includes as one of its units a cooling tank, both arrangements being herein disclosed. In either case, the water, when first admitted into the air stream, is at a temperature much cooler than are the impellers which compress the air, the result being that,

for a given ripJn. of pump operation, the temperature of the air discharged from the delivery side of the pump is definitely reduced. This cooling capability assures an increased margin of safety permitting the pump operation to be speeded up to produce a higher cim. output while still remaining within safe thermal limits.

A lobular type of pump, equipped with the means herein described, may optionally utilize water contained in a closed circulation system having an adequate cooling unit therein, or take water direct from a circulating line, whichever is most convenient. In the arrangement illustrated, the valve 64 may be turned. to one of its three positions to (1) open up communication to the water circulating line 63 and close communication to the tank, or (2) reverse these lines of communication ,so as to close off communication with the line 63 and establish communication with the tank, or (3) shut off communication with both the line 63 and tank, should there be any occasion for so doing. present sealant-coolant system, when applied to a lobular type of pump, as aforesaid, may be provided with means for connecting either with a line or tank, according as may be specified, or to both as herein shown, with a valve operable to establish communication selectively with either. Water is the liquid medium most commonly available, so has been referred to as the liquid to be used;

It is to be understood that the;

it should be understood, however, that other suitable liquids may be used in lieu of water as, for example, an anti-freeze composition, where pumping operations are to be conducted in a below-freezing temperature.

I claim:

1. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery from a supply source into the air inlet or" a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state on route to the clearance spaces between and around the impellers to provide a continuously moving atomized sealant therefor, the liquid supply source being contained in a cooling tank communicating with the air outlet to provide one unit in a closed conduit system through which the liquid may be continuously circulated, a float-controlled valve through which liquid may be admitted into the tank for accumlation therein up to a level where an air space is maintained thereabove, and a discharge opening communicating with the tank air space adapted to educt heated air therefrom into the surrounding atmosphere.

2. Means means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery from a supply source into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously moving atomized sealant therefor, the liquid supply source being contained in a cooling tank communicating with the air outlet to provide one unit in a closed conduit system through which the liquid may be continuously circulated, the walls of the tank being formed of metal having a high heat conductivity with a plurality of fins formed exteriorly thereof to promote dissipation of heat therefrom whereby to accelerate cooling or" the liquid circulating therewithin.

3. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously-moving atomized sealant therefor, and a fixedly-mounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivering controlled quantities of liquid into the air inlet being extended through a wall of the head at a level below the open-top of the air inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to com-mingle with the downflowing air stream therein.

4. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a con tinously-moving atomized sealant there-for, a fixedlymounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening 'therethrough, the means for delivering controlled quantities of liquid into the air inlet being extended through a wall thereof at a level below the open-top of the air inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to cornmingle with the downflowing air stream therein, and a shield fixedly mounted intermediately of the tops of the head and air inlet transversely of their axes and in spaced relation to each, the shield having its peripheral portion downturned to a level elow the open top of the air inlet and inwardly spaced from the side walls of the head to provide therebetween an annular space for downward flow of the air stream entering into the chambered head through its top opening, the air stream so passing the shield then impinging upon the pool surface for deposit thereon of foreign particles carried thereby preliminary to an inward and then upward turn of the air stream under the shield requisite for entering into the open top of the air inlet.

5. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously moving atomized sealant therefor, a fixedlymounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top or" said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivering controlled quantities of liquid into the air inlet being extended through a wall of the head at a level below the open-top of the air inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to commingle with the downllowing air stream therein, and means between the tops of the head and air inlet acting to deflect the downflowing air stream outwardly for direct impingement upon the surface of the pool to deposit thereon foreign particles carried by the air stream preliminary to a reactive inward movement of the air stream requisite for its entering into the open-top of the air inlet.

6. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity or" liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously-moving atomized sealant therefor, a fixedly-mounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivering controlled quantities of liquid into the air inlet being extended through a wall of the head at a level below the open-top of the air inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to commingle with the downflowing air stream therein, and means between the tops of the head and air inlet acting to deflect the downflowing air stream outwardly for direct impingement upon the surface of the pool to deposit thereon foreign particles carried by the air stream preliminary to a reactive inward movement of the air stream requisite for its entering into the open-door of the air inlet.

7. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into atomized state on route to the clearance spaces between and around the impellers to provide a continuously-moving atomized sealant therefor, a fixedlynnounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivering controlled quantities of liquid into the air inlet being extended into the head at a level below the open-top of said inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to commingle with the downflowing air stream therein, a shield fixedly supported intermediately of the tops of the head and air inlet transversely of their axes and in spaced relation to each, the shield having its peripheral portion downturned to a level below the open-top of the air inlet and inwardly spaced from the side walls of the head to provide therebetween an annular space for downward flow of the air stream entering into the chambered head through its air opening, the air stream so passing the shield then impinging upon the pool surface for deposit thereon of foreign particles carried thereby preliminary to an inward and then upward turn of the air stream under the shield requisite for entering into the open-top of the air inlet therebelow, and a plurality of spaced-apart ports extended through the air inlet at a common level approximating that at which liquid is delivered into the head, thereby to admit liquid into the interior of the air inlet at spaced points circumferentially thereof.

8. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously-moving atomized sealant therefor, a fixedly-mounted head de fining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivering liquid into the air inlet being extended into the head at a level below the open-top of the air inlet whereby liquid accumulating within the annular space between the head and air inlet will form therein a reserve pool from which the liquid is drawn into the air inlet to commingle with the downflowing air stream therein, the delivery means including an orifice of restricted size to control the liquid passing therethrough in an amount directly proportionate to the impeller-created pressure differential existing between opposite sides of the pump.

9. Means for sealing clearance spaces between and around rotatable impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for dis charge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state on route to the clearance spaces between and around the impeller-s to provide a continuously-moving atomized sealant therefor, a fixedly-mounted head defining a closed chamber surrounding the air inlet in spaced relation thereto with its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, means for delivering controlled quantities of liquid into the air. inlet being extended through a wall of the head at a level below the open-top of the air inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which the liquid is drawn into the air inlet to commingle with the downflowing air stream therein, and a normally-open check valve, connected with the bottom of the head for drainage of liquid therefrom, adapted to be closed in response to the impeller-created pressure differential existing between opposite sides of the pump.

it Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described wherein is an elongated open-top air inlet and an air outlet for discharge of air therethrough, comprising means for delivery into the air inlet of a controlled quantity of liquid to be dispersed therein upon contact with a swiftly moving air stream flowing through the air inlet in response to operation of the pump, the liquid so dispersed being commingled with the air stream for conversion into an atomized state en route to the clearance spaces between and around the impellers to provide a continuously-mow ing atomized sealant therefor, a fixedly-mounted head defining a closed chamber surrounding the air inlet in spaced relation thereto having its bottom in sealed connection therewith and its top extending over the open-top of said inlet in spaced relation thereto and formed with an air opening therethrough, the means for delivery controlled quantities of liquid into the air inlet being extended through a wall of the head at a level below the open-top of said inlet whereby liquid accumulating within the annular space interiorly of the head will form therein a reserve pool from which liquid is drawn into the air inlet to commingle with the downtlowing air stream therein, means between the tops of the head and air inlet acting to deflect the downtlowing air stream outwardly for direct impingement upon the surface of the pool to deposit thereon foreign particles carried by the air stream preliminary to a reactive movement of the air stream requisite for its entering into the open-top of the air inlet, and a normally-open check valve, connected with the bottom of the head for drainage of particle-laden liquid therefrom, adapted to be closed in response to the impeller-created suction force maintained in the head during periods of pump operation.

11. The method of mixing and supplying finely dispersed water-air directly to lobular impellers and to the interior of a close fitting housing therefor, the method comprising introducing air into an opening in the pump housing, providing a source of water in communication with the said opening, controlling the amount of water passing into the said opening, the air passing into said opening directly contacting the water flowing therethrough and effecting fine dispersion of the water and air, and supplying the finely dispersed water and air directly to the exterior surfaces of the lobular impellers and thus providing a continuously moving sealant between same and the housing.

12. Means for sealing clearance spaces between and around rotatable lobular impellers and a closely surrounding housing therefor in a pump of the kind described having an air inlet and an air outlet for discharge of air therethrough, comprising providing air inlet means to the housing, means for delivering a controlled quantity of liquid into said air inlet means, means for admitting air into the air inlet means for movement swiftly therethrough toward the pump in response to operation thereof, and means for effecting impingement of the swiftly moving air directly upon the liquid delivered into the air inlet means in a manner to effect dispersion of the liquid in atomized fine particle form in the moving air, and directing the finely dispersed airborne liquid directly into the clearance spaces between and around exterior surfaces of the impellers and the interior surfaces of the housing to provide a continuous dispersed fluid sealant between the same.

13. The invention as defined by claim 12, wherein said air inlet means comprises an elongate nipple constituting an atomizing chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,148,809 8/1915 White 230-205 2,227,441 1/1941 Coleman 230-205 X 2,460,814 2/1949 Duerr 230-207 ROBERT M. WALKER, Primary Examiner. 

1. MEANS FOR SEALING CLEARANCE SPACES BETWEEN AND AROUND ROTATABLE LOBULAR IMPELLERS AND A CLOSELY SURROUNDING HOUSING THEREFOR IN A PUMP OF THE KIND DESCRIBED WHEREIN IS AN ELONGATED OPEN-TOP AIR INLET AND AN AIR OUTLET FOR DISCHARGE OF AIR THERETHROUGH, COMPRISING MEANS FOR DELIVERY FROM A SUPPLY SOURCE INTO THE AIR INLET OF A CONTROLLED QUANTITY OF LIQUID TO BE DISPERSED THEREIN UPON CONTACT WITH A SWIFTLY MOVING AIR STREAM FLOWING THROUGH THE AIR INLET IN RESPONSE TO OPERATION OF THE PUMP, THE LIQUID SO DISPERSED BEING COMMINGLED WITH THE AIR STREAM FOR CONVERSION INTO AN ATOMIZED STATE EN ROUTE TO THE CLEARANCE SPACES BETWEEN AND AROUND THE IMPELLERS TO PROVIDE A CONTINUOUSLY MOVING ATOMIZED SEALANT THEREFOR, THE LIQUID SUPPLY SOURCE BEING CONTAINED IN A COOLING TANK COMMUNICATING WITH THE AIR INLET TO PROVIDE ONE UNIT IN A CLOSED CONDUIT SYSTEM THROUGH WHICH THE LIQUID MAY BE CONTINUOUSLY CIRCULATED, A FLOAT-CONTROLLED VALVE 